Two part or multi-component dispensing systems for dispensing resins, adhesives, acrylic materials, urethanes, and the like are of course well-known and are currently marketed by various manufacturers, such as, for example, EMC.sup.2 of Sterling Heights, Michigan, GS Manufacturing of Costa Mesa, Calif., and Ashby Cross Company, Inc. of Topsfield, Mass. While the systems manufactured and marketed by such companies are of course satisfactory from an operational point of view, several operational drawbacks or disadvantages commonly characteristic of such systems do exist.
For example, most of the known multi-component dispensing systems comprise a drive motor operatively connected to a pair of metering pumps which serve to dispense, for example, an adhesive material and an associated activator. In accordance with a first well-known type of system, however, the metering pumps are usually gear driven by means of a driving gear mounted upon the drive motor. Consequently, if it is desired to change or alter the relative outputs, amounts, or ratios of the adhesive and activator components being dispensed, due for example to the fact that a different proportion or ratio of the resin or adhesive material with respect to its associated activator is required to be used as a result of the use of different adhesives in connection with different applications, or as a result of the use of particular resins or adhesives under different operating or ambient temperature conditions, the conventional dispensing systems cannot readily accommodate or achieve such alterations or changes without major changes or alterations to the drive motor and metering pump assemblies. In particular, for example, the size of the drive motor driving gear, or the size of the metering pump driven gears enmeshed with the drive motor driving gear, cannot be readily changed or altered because the drive motor and metering pumps are mounted at relatively fixed positions with respect to each other. Accordingly, changing the size of the various driving or driven gears alters the center-to-center distances defined between the driving and driven gears which cannot be physically accommodated within the system.
In accordance with a second well-known type of system, the metering pumps are operatively driven by the drive motor through means of a suitable chain drive mechanism or system. However, again, in order to alter or change the output drive of the metering pumps, the various sprocket components, chains, idlers, and the like need to be changed which is quite time-consuming and results in a substantially extensive amount of system down-time. In addition, it is also important that the resin or adhesive metering pump and the activator metering pump be able to be separately or independently operated or driven by means of the drive motor. There are several reasons for this requirement. Firstly, it is important to operate the metering pumps separately or independently in order to properly calibrate or test the pumps so as to ensure, for example, that each pump is dispensing the desired amount of material. Along these lines, it is important to be able to calibrate the metering pumps separately or independently in order not to waste material which would therefore be dispensed by means of the other metering pump not being calibrated or tested.
Secondly, in a similar manner, if one of the metering pumps develops, experiences, or exhibits an operational problem, it is again important from the viewpoint of being able to conserve resources or materials to be able to service or perform required maintenance upon such inoperative metering pump without having to operate or run the operative metering pump. In accordance with the conventional chain-driven drive motor and metering pump systems, however, such separate or independent operation of the metering pumps is not possible because both metering pumps are driven by the drive motor in a serial manner. In other words, the driving arrangement is such that the drive motor is operatively connected to a first one of the metering pumps so as to drive such metering pump, and such first metering pump is then in turn operatively connected to the second metering pump. Consequently, in view of the fact that both of the metering pumps are not directly driven by the drive motor, but to the contrary, the second metering pump is driven by the first metering pump, both metering pumps are not able to be separately or independently driven by the drive motor. If the second metering pump is to be driven or operated, then the first metering pump must also be driven or operated.
A need therefore exists in the art for a new and improved resin or adhesive dispensing system wherein the relative amount of a resin or an adhesive to be dispensed, with respect to its associated activator, can be readily and easily changed or altered depending upon the particular resin or adhesive being dispensed, the operating or ambient temperature conditions, and the like, such that a predeterminedly desired ratio of resin or adhesive with respect to its associated activator is achieved. In addition, there is also a need in the art for a new and improved adhesive or resin dispensing system wherein the adhesive or resin and activator metering pumps are capable of being separately and independently driven by means of the drive motor such that each one of the metering pumps can be separately and independently calibrated, serviced, and maintained without operating the other metering pump such that resin, adhesive, or activator materials are not needlessly wasted.